Method and drive system having a device for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine

Abstract

The invention relates to a method for sensorless determination of the angular frequency (ωe) and / or position (φe) of a permanent magnet rotor of a brushless electric machine (1), in particular of a linear or rotary machine, wherein a d-voltage (υd) and a q-voltage (υq}) are provided to the electric machine (1), wherein the d-voltage (υd), in the context of an injection process, is a high-frequency d-test signal voltage (υd,inj) with a predefined carrier frequency, wherein a plurality of phase currents (i 1, i 2) of the machine (1) are measured and a demodulated current (i q_dem ) is determined on the basis of the measured phase currents (i 1, i 2), wherein a d-voltage deviation (Δυd) and a q-voltage deviation (Δυq) are determined using an, in particular mathematical, motor model (9), wherein, in a fusion device (6), the angular frequency (ωe) and / or position (φe) of the permanent magnet rotor is determined on the basis of the demodulated current (i q_dem ), the d-voltage deviation (Δυd)) and the q-voltage deviation (Δυq), wherein the fusion device (6) has a controller (22) having an I component, in particular an I controller, to which a summed signal is fed which is dependent on the demodulated current (i q_dem ) and the d-voltage deviation (Δυ_d) and the q-voltage deviation (Δυq) and feedback of the determined angular frequency (ωe) and / or position ((φe) of the permanent magnet rotor.

Description

[0001] P241229 1

[0002] Method and drive system with a device for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine

[0003] The invention relates to a method for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine. Furthermore, the invention relates to a drive system with a device for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine.

[0004] Brushless electric machines with a permanent magnet rotor are also known as permanent magnet electric machines and are increasingly used in the automotive industry, particularly in the form of permanent magnet synchronous motors. Controlling such electric machines requires knowledge of the permanent magnet rotor's position. Conventionally, this position is determined using a position sensor, but this involves additional costs and installation space. Therefore, there is a need for sensorless alternatives for controlling these machines.

[0005] An exemplary method for the sensorless determination of the position and angular frequency of a permanent magnet rotor is known from EP 2019482 A1. The method is used within the framework of field-oriented control (vector control) and enables the determination of the rotor's angular frequency based on multiphase current measurements at the machine. A mathematical machine model is used for angular frequency and position estimation.

[0006] Another method for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine is described in EP 2023479 A1. In this method, a mathematical machine model provides an angular frequency and position estimate in the higher angular frequency range. At lower angular frequencies and when stationary, an injection method is used in which periodic test signals of a predetermined carrier frequency are injected into a manipulated variable, in this case the so-called d-voltage. The phase currents of the machine are measured and evaluated for position-dependent anisotropy in the magnetic structure of the electric machine, from which the angular frequency and / or position of the permanent magnet rotor is deduced. Fig. 1 shows a block diagram of a drive system that implements the method described in EP 2023 P241229 2.

[0007] To enable a transition between the angular frequency and position estimation by the machine model and by the injection method, a fusion device is provided, the setup of which is shown in Fig. 2. The fusion device comprises a model tracking controller 30, an injection tracking controller 31, and a combination device 50, which combines the estimation values ​​provided by the two tracking controllers. The outputs of the model tracking controller 30 and the injection tracking controller 31 are added together. Both the model tracking controller 30 and the injection tracking controller 31 have controllers with an integrating component, I-component. It has been found that in situations where the electric machine rotates slowly, the outputs 23, 49 of the model tracking controller 30 and the injection tracking controller 31 can drift in different directions and increase in magnitude in an uncontrollable manner.Due to the low angular frequencies G). e With a high or close-to-1 weighting factor F, such an uncontrollable effect on the determined angular frequency G) e out of.

[0008] In the range of higher angular frequencies G) e The weighting factor F is zero. Therefore, the output 49 of the injection tracking controller 31 has no effect on the estimated angular frequency o) e Noise at input 47 of the injection tracking controller 31 can be integrated into it and lead to an undesirably high value at output 49 of the injection tracking controller 31. As soon as the angular frequency of the electric machine decreases and the weighting factor F increases, a high value at output 49 of the injection tracking controller 31 can also lead to an uncontrolled increase in the determined angular frequency (n). eThis behavior can lead to instability or even the crash of the control system.

[0009] Against this background, the task arises to increase the stability of the sensorless control of a brushless electric machine.

[0010] The problem is solved by a method for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine, in particular a linear or rotary machine, wherein a d-voltage and a q-voltage are provided to the electric machine, wherein a high-frequency d-test signal voltage with a predetermined carrier frequency is superimposed on the d-voltage within the framework of an injection method, wherein several phase currents of the machine are measured and a demodulated current is determined on the basis of the measured phase currents, wherein a d-voltage deviation and a q-voltage deviation are determined on the basis of a motor model, in particular a mathematical one, wherein in a fusion device the P241229 3

[0011] The angular frequency and / or position of the permanent magnet rotor is determined based on the demodulated current and the d-voltage deviation and the q-voltage deviation, wherein the fusion device has a controller with an I-component, in particular an I-controller, to which a sum signal is supplied which depends on the demodulated current and the d-voltage deviation and the q-voltage deviation and a feedback of the determined angular frequency and / or position of the permanent magnet rotor.

[0012] For the purposes of this invention, a controller with an integral component is understood to be a controller with an integrating component. Accordingly, an integral controller is an integrating controller.

[0013] Since the controller with an integral component receives the sum signal, which depends on the demodulated current, the d-voltage deviation, and the q-voltage deviation, no further controllers with an integral component are required to determine the angular frequency and / or position of the permanent magnet rotor. Because the sum signal fed to the controller with an integral component also depends on the feedback of the determined angular frequency and / or position of the permanent magnet rotor, the controller with an integral component is thus arranged in a closed control loop. This measure reduces the risk of the fusion device becoming unstable due to an uncontrollable increase or overflow of the output of the controller with an integral component. Consequently, the stability of the sensorless control of a brushless electric machine can be increased.

[0014] According to an advantageous embodiment of the invention, the demodulated current is weighted with a weighting factor that depends on the determined angular frequency. Such an embodiment represents a further contrast to the prior art, in which not the demodulated current, but rather an output of an injection tracking controller is weighted with a weighting factor.

[0015] According to an advantageous embodiment of the invention, the weighting factor is maximal for a determined angular frequency of 0 and decreases for a larger determined angular frequency. Such a characteristic allows the influence of the injection method on the low angular frequency range of the electric machine to be limited.

[0016] According to an advantageous embodiment of the invention, the demodulated current is supplied to a controller with a proportional (P) component, in particular a proportional (P) controller, and an output of the controller with a proportional (P) component is used to generate the summed signal. P241229 4

[0017] For the purposes of this invention, a controller with a P-component is understood to be a controller with a proportional component. A P-controller is therefore a proportional controller. This approach prevents the outputs of several controllers with an I-component from being added together and leading to an uncontrollable increase in the measured angular frequency.

[0018] According to an advantageous embodiment of the invention, the demodulated current is fed to a controller with a proportional (P) component, in particular a proportional (P) controller, and an output of the controller with a P component is summed with an output of the controller with an integral (I) component to obtain the determined angular frequency. This summation allows for an angular frequency estimate that depends on both the demodulated current and the d-voltage deviation and the q-voltage deviation.

[0019] To solve the aforementioned problem, a drive system is further proposed with a device for sensorless determination of the angular frequency and / or position of a permanent magnet rotor of a brushless electric machine, in particular a linear or rotary machine, which is configured to provide the electric machine with a d-voltage and a q-voltage, to impose a high-frequency d-test signal voltage with a predetermined carrier frequency on the d-voltage within the framework of an injection method, to measure several phase currents of the machine and to determine a demodulated current based on the measured phase currents, and to determine a d-voltage deviation and a q-voltage deviation based on a motor model, in particular a mathematical one, wherein the device comprises a fusion device.by which the angular frequency and / or position of the permanent magnet rotor can be determined based on the demodulated current and the d-voltage deviation and the q-voltage deviation, wherein the fusion device has a controller with an integral component, in particular an integral controller, to which a sum signal can be supplied which depends on the demodulated current and the d-voltage deviation and the q-voltage deviation and a feedback of the determined angular frequency and / or position of the permanent magnet rotor.

[0020] The drive system according to the invention can achieve the same technical effects and advantages that have already been explained in connection with the method according to the invention.

[0021] According to an advantageous embodiment of the invention, the demodulated current is weighted with a weighting factor that depends on the determined angular frequency. Such an embodiment is in contrast to the prior art of P241229 5

[0022] Technique in which not the demodulated current, but an output of an injection tracking controller is weighted with a weighting factor.

[0023] According to an advantageous embodiment of the invention, the weighting factor is provided that it is maximal for a determined angular frequency of 0 and decreases for a determined angular frequency that is larger in absolute value.

[0024] According to an advantageous embodiment of the invention, the fusion device comprises a controller with a proportional (P) component, in particular a proportional (P) controller, to which the demodulated current can be supplied, with an output of the controller with the P component being used to generate the summed signal. Such a characteristic allows the influence of the injection method on the low angular frequency range of the electric machine to be limited.

[0025] According to an advantageous embodiment of the invention, the fusion device comprises a controller with a proportional component, in particular a proportional controller, to which the demodulated current can be supplied, wherein the fusion device has a summing element for summing an output of the controller with a proportional component with an output of the controller with an integral component in order to obtain the determined angular frequency.

[0026] Further details and advantages of the invention will be explained below with reference to the exemplary embodiment shown in the drawings. This shows:

[0027] Fig. 1 shows a block diagram of a drive system according to the prior art;

[0028] Fig. 2 shows a block diagram of a fusion device of the drive system according to Fig. 1; and

[0029] Fig. 3 shows a block diagram of a fusion device according to an embodiment of the method and drive system according to the invention.

[0030] The illustration in Fig. 1 shows a drive system that can be used, for example, in the automotive industry. The drive system comprises an electric machine 1 with a stator and a permanent magnet rotor, for example, a brushless synchronous machine. A control device is provided to regulate the position and angular frequency of the rotor of the electric machine 1, which implements field-oriented control (vector control). P241229 6

[0031] The control device 100 comprises two controllers 111, 112, via which a d-voltage u d and a q-voltage u q These stresses are provided in the rotor-related dq coordinate system. d and u qare fed to a transformation unit 7, in which a transformation from the rotor-related dq coordinate system to the stator-related a-β coordinate system is performed. The stator-related voltages u obtained at the output of transformation unit 7 a and u ß The currents are fed to a unit 8 for space vector modulation (SVM), which controls a converter 2 using pulse width modulation (PWM). This converter 2 provides several, here two, phase currents for the winding of the stator of the electric machine 1.

[0032] Two phase currents i1 and i2 of the stator are measured via current sensors 41, 42 and fed to further transformation units 3, 4, which transform the phase currents into the rotor-related dq coordinate system. The actual currents i are obtained in this process. d and i q These actual flows i d , i q are fed to a notch filter 4a, which has a blocking frequency MC exhibits a carrier frequency that corresponds to an injection method, which will be explained further below. Filter 4a can be used to filter out high-frequency components generated by the injection method in the actual currents i d , i q They are filtered out so that they do not affect the regulation. The filtered actual flows i d , i q These actual values ​​are then fed to controllers 111 and 112. Further input signals to controllers 111 and 112 are the setpoint values, i. d so u, i q-S oii-

[0033] For sensorless determination of the angular frequency and position of the permanent magnet rotor, the drive system, according to the prior art, provides two complementary mechanisms. At standstill and in the low angular frequency range, an injection method (blocks 36, 32) is used, while at higher angular frequencies, a mathematical motor model 9 is employed. The values ​​obtained via both mechanisms, in particular angular frequency and / or position values, are fused in a fusion device 6 to determine the angular frequency G). e and the location p e to determine the rotor frequency of electric machine 1. In addition, a low-pass filtered angular frequency G) is used. et provided.

[0034] The mathematical motor model 9 is assigned the filtered angular frequency

[0035]

[0036] and the filtered angular frequency G) etfed into the mathematical motor model 9 are the filtered actual currents i. d f and i q _ f and the control variables d-voltage u d and q-voltage u q supplied. The mathematical motor model 9 determines a d-voltage deviation Au. d and P241229 7

[0037] a q-voltage deviation Δu q , which are output to a model tracking controller 30. The model tracking controller 30 determines an angular frequency, which is also referred to here as the model angular frequency and is provided at output 23.

[0038] To implement the injection process, the drive system comprises an injection block 36, a demodulation block 32 and an injection tracking controller 31.

[0039] In injection block 36, a high-frequency d-test signal voltage u is applied. o sin(ü) c t) with a given carrier frequency Ü) Cgenerated, which affects the d-voltage u d The imprinting is carried out via a multiplier 38, in which the d-test signal voltage is multiplied by an output of a hysteresis switching element 39. The switching element 39 is driven by the filtered angular frequency.

[0040]

[0041] controlled. The magnitude of the filtered angular frequency is...

[0042]

[0043] Within a window defined by the cutoff frequencies of switching element 39, switching element 39 outputs the value "1" and the high-frequency d-test signal voltage is switched through to be superimposed on the d-voltage. If the filtered angular frequency (n) ef However, if the value is outside the window, switching element 39 outputs the value “0” and the imprinting of the d-test signal voltage onto the d-voltage is interrupted.

[0044] The demodulation block 32 receives the unfiltered actual currents i as input signals. d , i q and determines a demodulated current i q _ dem The demodulated current i q _ dem is fed to the injection tracking controller 31. The injection tracking controller 31 is implemented as a proportional integral controller, PI controller, via whose output 49 an injection angular frequency is output.

[0045] In the combination device 50, the model angular frequency and the injection angular frequency are fused. Thus, the combination device 50 can provide (estimated) values ​​of the angular frequency G). e and the location p e spend.

[0046] The determined location p e is forwarded to the controller 100, in particular the transformation units 7, 4, and is taken into account there during the transformation from the stator-related to the rotor-related coordinate system or vice versa.

[0047] A detailed representation of the fusion device 6 of the drive system according to the prior art is shown in Fig. 2. The fusion device 6 receives the d-voltage deviation Δu as input values. d and the q-voltage deviation Δu q as well as the demodulated current i q_dem The fusion device 6 determines the angular frequency ω. e and the location φ e of P241229 8

[0048] Permanent magnet rotor of the electric machine. The angular frequency a> e is filtered through a low-pass filter E to obtain a filtered angular frequency

[0049]

[0050] to obtain. The location p e the permanent magnet rotor is generated by an integrator 24 from the angular frequency G) e derived.

[0051] The fusion device 6 comprises several controllers 22, 31 with an integrating component. Firstly, the model tracking controller 30 includes an integrating controller 22. This controller receives a sum calculated from the q-voltage deviation u. q 19 and an output signal of a proportional controller 20. The proportional controller 20 is supplied with the d-voltage deviation Au, weighted by a factor G. d 18 supplied. The factor G depends on the filtered determined angular frequency ü). ef In particular, the factor G is for an angular frequency

[0052]

[0053] > ü) e0 equal to 1 and for an angular frequency

[0054]

[0055] < -w e0 equals -1. For an angular frequency - e0

[0056]

[0057] < < <^ e o the factor G = ü) ef . Secondly, the injection tracking controller 31 includes an I-component.

[0058] The fusion device 6 comprises a summing element 51, which adds the output 23 of the model tracking controller 30 and the output 49 of the injection tracking controller 31, weighted by a factor F. The factor F is determined for a filtered angular frequency.

[0059]

[0060] = 0 maximum and is 1. For a larger absolute value filtered angular frequency

[0061]

[0062] the factor decreases in magnitude and has the sign of the angular frequency ) ef up. For angular frequencies oj ef > a> e0 and oh ef < —a> e0 The factor F = 0.

[0063] In the prior art fusion device 6, it has proven disadvantageous that both the model tracking controller 30 and the injection tracking controller 31 have a controller with an integrating component, I-component. In situations where the electric machine 1 rotates slowly, the angular frequency G) e Therefore, if the factor F is low, it is high. Consequently, the outputs 23, 49 of the model tracking controller 30 and the injection tracking controller 31 may drift in different directions and increase uncontrollably in magnitude.

[0064] In the range of higher angular frequencies G) e The weighting factor F is zero. Therefore, the output 49 of the injection tracking controller 31 has no effect on the estimated angular frequency (n). e However, noise at input 47 of the injection tracking controller 31 can lead to high values ​​at output 49 of the injection tracking controller 31 due to the integral component. As soon as the angular frequency > e As the electrical machine 1 decreases again and the weighting factor F subsequently increases, a high value at output 49 of the injection P241229 9 can occur.

[0065] Tracking controller 31 also leads to an uncontrolled increase in the determined angular frequency o) e This behavior can lead to instability or even the crash of the control system.

[0066] Fig. 3 shows an embodiment of a fusion device 6 according to the invention, in which measures are taken to enable stable control behavior.

[0067] The fusion device 6 according to the invention does not generate either a model angular frequency or an injection angular frequency. Rather, the fusion device 6 according to the invention comprises exactly one controller 22 with an integral component, in particular an integral controller, to which a sum signal is supplied that depends on the demodulated current i. q _ dem and the d-voltage deviation Au d and the q-voltage deviation u q and a feedback of the determined angular frequency G) e of the permanent magnet rotor. In this respect, the controller 22 of the model tracking controller 30 is also used to calculate the integral component of both the injection tracking controller and the permanent magnet rotor.

[0068] The demodulated current i q dem The signal is first multiplied by the weighting factor F in a multiplier 52 and then fed to a proportional (P) controller 31. The output 49 of this P controller is connected on one side to the summing element 51 and on the other side, via a transfer element 101, to the summing element 102, which generates the aforementioned summed signal for the controller 22. In this respect, the P controller 31 from Fig. 3 corresponds to the proportional component of the injection-tracking controller 31 from Fig. 2. The gain of this proportional component is denoted by k2. In the embodiment according to the invention shown in Fig. 3, the integral component of the injection-tracking controller 31 from Fig. 2 is implemented by the integral controller 22, in that the outputs of blocks 31 and 21 are each connected to the summing element 102 via the additional proportional (P) components 101 and 103. The transfer factors of members 101 and 103 are each set to the values ​​— and — so that the desired reset time of the

[0069]

[0070] The injection tracking controller or the desired integral gain of the model tracking controller according to Fig. 2.

[0071] The fusion device 6 according to the embodiment of the invention contains neither an addition of the outputs of two independent integrators nor an "open" integration. The only integrator, namely the I-controller 22, is located in a closed loop with feedback. Therefore, there is no risk of instability of the algorithm P241229 10.

[0072] due to an uncontrollable increase or overflow of the integrator's output.

[0073] The fusion device shown in Fig. 3 can be used in a drive system with a device 100 for sensorless determination of the angular frequency G) e and / or location p e a permanent magnet rotor of a brushless electric machine 1, for example as shown in Fig. 1, can be used.

Claims

P241229 11 Patent claims 1. Method for sensorless determination of the angular frequency (o> e ) and / or location ( <p e ) of a permanent magnet rotor of a brushless electric machine (1), in particular a linear or rotary machine, wherein the electric machine (1) is supplied with a d-voltage (u d ) and a q-voltage (u q ) is provided, where the d-voltage (u d ), as part of an injection procedure, a high-frequency d-test signal voltage (u d_inj ) is imprinted with a predetermined carrier frequency, wherein several phase currents (i1,i2) of the machine (1) are measured and based on the measured phase currents a demodulated current (i q _ dem ) is determined, whereby a d- voltage deviation (Au) is determined using a motor model (9), in particular a mathematical one. d ) and a q-voltage deviation ( Au^) is determined, wherein in a fusion device (6) the angular frequency (o> e ) and / or location ( <p e ) of the permanent magnet rotor based on the demodulated current (i q dem ) and the d-voltage deviation (Au d ) and the q-voltage deviation (Au^) is determined, characterized by the fact that the fusion device (6) has a controller (22) with an I-component, in particular an I-controller, to which a sum signal is supplied which depends on the demodulated current (i q dem ) and the d-voltage deviation (Au d ) and the q-voltage deviation (Au^) and a feedback of the determined angular frequency (o> e ) and / or location ( <p e ) of the permanent magnet rotor.

2. Method according to claim 1, characterized in that the demodulated current (i q_dem ) is weighted with a weighting factor that depends on the determined angular frequency (ω)e is dependent on.

3. Method according to claim 2, characterized in that the weighting factor for a determined angular frequency (o> e ) of 0 is at its maximum and for a larger determined angular frequency (o> e ) decreases.

4. Method according to one of the preceding claims, characterized in that the demodulated current (i q dem ) a controller with a proportional (P) component, in particular a P241229 12 A P-controller is supplied with a signal, and an output of the controller with a P-component is used to form the sum signal.

5. Method according to one of the preceding claims, characterized in that the demodulated current (i q dem ) is fed to a controller with a proportional (P) component, in particular a P-controller, and an output of the controller with a proportional (P) component is summed with an output of the controller with an integral (I) component to determine the angular frequency (o> e ) to obtain.

6. Drive system with a device (100) for sensorless determination of the angular frequency (ü) e ) and / or location ( <p e ) of a permanent magnet rotor of a brushless electric machine (1), in particular a linear or rotary machine, which is designed to of the electric machine (1) a d-voltage (u d ) and a q-voltage (u q ) to provide, the d-voltage (u d ), as part of an injection procedure, a high-frequency d-test signal voltage (u d_inj ) to imprint with a predetermined carrier frequency, to measure several phase currents (i1, i2) of the machine (1) and to measure a demodulated current (i q_dem ) to determine, based on the measured phase currents (i1, i2), a d-voltage deviation (Au) based on a motor model (9), in particular a mathematical one. d) and to determine a q-voltage deviation (Au^), wherein the device (100) comprises a fusion device (6) by which the angular frequency (o> e ) and / or location ( <p e ) of the permanent magnet rotor based on the demodulated current (i q dem ) and the d-voltage deviation (Au d ) and the q- voltage deviation (Au^) can be determined, characterized by the fact that the fusion device (6) has a controller (22) with an I-component, in particular an I-controller, to which a sum signal can be supplied which depends on the demodulated current (i q dem ) and the d-voltage deviation (Au d ) and the q-voltage deviation (Au^) and a feedback of the determined angular frequency (o> e ) and / or location ( <p e ) of the permanent magnet rotor.

7. Drive system according to claim 6, characterized in that the demodulated current (i q _ dem) is weighted with a weighting factor determined by the P241229 13 Angular frequency (o> e is dependent on.

8. Drive system according to claim 7, characterized in that the weighting factor for a determined angular frequency (o> e ) of 0 is at its maximum and for a larger determined angular frequency (o> e ) decreases.

9. Drive system according to one of claims 6 to 8, characterized in that the fusion device (6) has a controller with a P-component, in particular a P-controller, to which the demodulated current (i q dem ) can be supplied, whereby an output of the controller with a P-component is used to form the sum signal.

10. Drive system according to one of claims 6 to 9, characterized in that the fusion device (6) has a controller with a P-component, in particular a P-controller, to which the demodulated current (i q dem) can be supplied, wherein the fusion device (6) has a summing element for summing an output of the controller with a P-component with an output of the controller with an I-component to obtain the determined angular frequency (o> e ) to obtain.

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